If multiple guests are telling you the QR isn’t scanning, walk this list. Each fix takes a minute. The order is by frequency we see in practice.
1. Contrast is too low
By far the most common cause when QRs are printed against a colored background.
Check: Is the QR foreground darker than the background by at least 4.5:1 contrast? Pure black on white = perfect. Dark color on white = fine. Light color on white = problem. Dark color on dark = problem.
Fix: Use the foreground/background color picker on the Guest assets page; the contrast indicator warns you. If a card is already printed and unreadable, reprint with high contrast.
2. QR is too small
The QR needs to be at least 0.75 inches (2 cm) per side. Less and most phone cameras can’t lock focus on it.
Check: Measure with a ruler.
Fix: Reprint at a larger size. The default table-card PDF is 1.4 inches, which is the right size.
3. Venue lighting is too dim or too bright
Both ends of the lighting spectrum cause problems. Candlelit dinners → too dark for phone cameras to focus. Outdoor daytime weddings → glare on glossy paper washes out the contrast.
Fix for dim: Recommend that guests turn on their phone flash, OR move the QR placement closer to ambient lighting.
Fix for bright: Reprint on matte stock. Glossy reflects too much. If reprinting isn’t possible, suggest guests scan in a shaded spot.
4. Paper finish is reflective
Glossy and metallic finishes can defeat QR readers under any lighting.
Fix: Use matte or uncoated stock. Recycled cardstock works well — slightly textured but reads cleanly.
5. The phone is too old to read QR codes natively
iPhones from before 2017 (iOS 10 and below) and most Android phones from before 2018 don’t have native camera QR detection.
Fix: This is what the short URL below the QR is for. The PDF templates always include it. Tell the guest to type the short URL into their browser — it’s intentionally short (typically 4-6 characters after the domain) so this is fast.
Things that look like QR problems but aren’t
A few false positives to know about:
“It scanned but nothing happened.” The scan worked; the phone just didn’t show the banner. Have them open their camera app, point at the QR, and tap the URL banner that briefly appears at the top of the screen. Newer iPhones show a yellow chip; Androids show a notification.
“It opens but I get an error page.” The QR is fine; the URL is something else. Most likely the event isn’t active (test event that expired, or the wall date hasn’t started yet). Check the event status in the admin dashboard.
“My QR scanner app says invalid code.” Some third-party QR apps are aggressive about flagging non-standard URLs. Have them use the built-in camera app instead — it’s more permissive.
Prevent before the event
Three things to test 48 hours before:
- Print the actual asset on the actual paper. Not a draft, not a different stock.
- Scan from at least two different phones, ideally one iPhone and one Android.
- Test in venue lighting. This is the step everyone skips. Bring the printed cards to the venue during setup and scan them under the actual lighting.
If you do all three and both phones load the page in under 3 seconds, you’re safe to print the rest. If either fails, you have time to fix it.
What to do next
- Generate and print QR codes for guests for the upstream setup.
- Guests can’t upload photos if the QR scans but uploads fail.
- How guests upload photos for the full happy-path experience.